Comprehensive Description

General Description

A large (6.8-8.2 cm wingspan) moth with dark mottled grey forewings and dark red-orange hindwings, crossed by a broad black median band and a wide black terminal band. Unijuga is the largest and one of the most widely distributed of the Alberta Underwing moths. The dark red-orange (as opposed to pink) hindwings with wide black bands will separate it from all Alberta Catocala except meskei and briseus. Meskei is smaller, usually has paler and less mottled forewings and brighter red hindwings. There is also usually a small black spot at the lower end of the black median band on the hindwings, or a small upturned extension to this band. Meskei also lacks the many dark hairs in the basal area of the hindwings which give unijuga a darker, duller appearance. Briseus is smaller than unijuga, and has darker forewings with a characteristic prominent lighter patch with brown scaling on the outer half. A form of unijuga with the forewings sooty black and with the markings reduced to traces of the jagged white subterminal line (form agatha) is not uncommon in Alberta.